276 Florida Entomologist 92(2) June 2009

FEEDING, REPRODUCTION, AND DEVELOPMENT OF THE RED PALM (: ) ON SELECTED PALMS AND CULTIVARS IN QUARANTINE

ARTURO COCCO1 AND MARJORIE A. HOY Department of Entomology and Nematology, University of Florida, Bldg. 970, Natural Area Drive, Gainesville, FL, 32611-0629, USA

1Presently at Dipartimento di Protezione delle Piante, Sezione Entomologia Agraria, Università di Sassari, Via De Nicola 1, 07100 Sassari, Italy E-mail: [email protected]

ABSTRACT

The red palm mite, indica Hirst, an important pest of , banana, and date palms is a new invasive pest in the Western Hemisphere. The red palm mite (RPM) has been observed attacking and plantains in Dominica and in Florida (M. A. Hoy, A. Cocco, personal observation). In order to develop an efficient method to rear the RPM in quarantine for a classical biological control project, several banana and plantain varieties were tested as hosts for the RPM. Bananas are more desirable than coconut (a favored host plant) be- cause bananas are easier to rear in small cages and will produce new shoots quickly after pruning. Red palm mite females did not establish on the banana and plantain varieties (Dwarf Cavendish, Dwarf Nino, Gran Nain, Dwarf Zan Moreno, Dwarf Green, Truly Tiny, sumatrana × Gran Nain, Dwarf Puerto Rican, Rose, Nang Phaya, Misi Luki, Manzano, Lady Finger, Glui Kai, and Ebun Musak) of discs tested, but they established on coconut leaf discs. The could not be reared on potted banana trees (Glui Kai, Dwarf Green, and Nang Phaya varieties), but a multigenerational colony has been maintained on coconut trees and leaf discs. No RPM females survived on native palms tested (saw palmetto, cabbage palm, and dwarf palmetto), but RPM completed a generation on needle palm, with longer de- velopment time, higher mortality, and lower fecundity than when reared on coconut discs. Our results indicate that coconut leaf discs and trees are better hosts for rearing RPM in quarantine than banana, plantain varieties, or native palms tested. Quarantine tests and field observations suggest that the host range of RPM may not be as broad as some reports indicate because plants from which RPM adults and/or eggs have been collected might not be suitable for establishment of a multigenerational colony. More studies under natural con- ditions need to be conducted to evaluate the ability of R. indica to establish and spread on native and ornamental palms in natural landscapes in Florida.

Key Words: Raoiella indica, laboratory rearing, host plants, saw palmetto, dwarf palmetto, cabbage palm, needle palm, coconut

RESUMEN

El acaro rojo de la palmera, Raoiella indica Hirst, una plaga importante del coco, banano, y de la palmera datilera es una plaga nueva invasora del Hemisferio Occidental. El acaro rojo de la palmera (ARP) ha sido observado atacando bananos y plátanos en Dominica y en la Flo- rida (M. A. Hoy, A. Cocco, observación personal). Para desarrollar un método eficiente para criar el ARP en cuarentena para un proyecto de control biológico clásico, varias variedades de banano y plátano fueron probadas como hospederos para el ARP. Los bananos son mas de- seables que los cocos (una planta hospedera preferida) por que los banano son mas fáciles para criar en jaulas pequeñas y producen nuevos brotes rápidamente después de la poda. Las hembras del acaro rojo de las palmeras no se establecieron sobre las variedades de ba- nano y plátano (Dwarf Cavendish, Dwarf Nino, Gran Nain, Dwarf Zan Moreno, Dwarf Green, Truly Tiny, Musa sumatrana × Gran Nain, Dwarf Puerto Rican, Rose, Nang Phaya, Misi Luki, Manzano, Lady Finger, Glui Kai y Ebun Musak) en los discos de hojas probados, pero se establecieron en los discos de hojas del coco. Estos ácaros no pudieron ser criados en árboles de bananos en macetas (variedades Glui Kai, Dwarf Green y Nang Phaya), pero ha mantenido una colonia multigeneracional sobre árboles de coco y discos de hojas. Ningún hembra de ARP sobrevivió las palmas nativas probadas (saw palmetto, cabbage palm, and dwarf palmetto), pero ARP completo una generación sobre la “needle palm” (palmera de aguja), con un periodo de desarrollo mas largo, mortalidad mas alta y fecundidad mas baja que cuando fue criado sobre discos de coco. Nuestros resultados indican que los discos de la hoja de coco y los árboles de coco son mejores hospederos para criar ARP en cuarentena que las variedades de plátano, banano o las palmeras nativas probadas. Las pruebas en cuaren-

Cocco & Hoy: Laboratory Rearing of the Red Palm Mite 277

tena y las observaciones indican que el rango de los hospederos de ARP posiblemente no sea tan amplio como indican algunos informes porque las plantas sobre que han recolectado adultos y/o huevos de ARP pueden ser no apropiadas para el establecimiento de una colonia multigeneracional. Se necesitan realizar mas estudios bajo condiciones naturales para eva- luar la habilidad de R. indica para establecerse y esparcirse sobre palmeras nativas y orna- mentales en áreas naturales de la Florida.

The red palm mite, Raoiella indica Hirst (Ac- atory mites are being reared in quarantine on ari: Tenuipalpidae) (RPM), is a serious pest of eco- coconut leaf discs (H. Bowman & M.A. Hoy, un- nomically important fruit-producing trees such as published). Bananas and plantains were ob- coconut Cocos nucifera L. and banana Musa spp. served to be a suitable host for the RPM in Do- (Nagesha-Chandra & Channabasavanna 1984; minica and in Florida (M.A. Hoy, N. Commo- Welbourn 2006). In addition, significant infesta- dore, and A. Cocco, personal observation) and tions have been reported on the Phoe- were considered more appropriate for rearing in nix dactylifera L., plantains Musa spp., and orna- small spaces than the coconut palm because mental palms, including the Christmas palm they can be grown in small pots, fit into small Adonidia (= ) merrillii (Becc.) H. E. cages, and produce new shoots quickly after Moore, and the Mexican fan palm Washingtonia pruning so they can be reused several times in robusta H. Wendl (Zaher et al. 1969; Etienne & quarantine. Fletchmann 2006). The RPM was found in the Thus, we conducted rearing tests to determine for the first time in Martinique and whether R. indica could be reared on banana and Saint Lucia in 2004 (Fletchmann & Etienne plantain leaf discs or trees under quarantine con- 2004), and has now spread throughout the Carib- ditions outside the infestation zone. In addition, bean islands and invaded Florida and Venezuela the suitability of selected Florida native palms as (Kane et al. 2005; Etienne & Fletchmann 2006; hosts for the RPM was investigated. Native palms Gutiérrez et al. 2007; Rodrigues et al. 2007). Rao- commonly occur in natural landscapes and the iella indica was detected in southeastern Florida fan-shaped palm could provide wider leaf in 2007 and is now established in 3 counties (Flor- discs than the split-leafed coconut palms for bio- ida Department of Agriculture and Consumer assays with the phytoseiids being evaluated in Services 2008). Plants reported by USDA-APHIS quarantine. In addition, these trials could provide to be hosts of R. indica in Florida include orna- new biological information about the host range mental palms such as the Fiji fan palm Pritchar- and the behavior of the RPM. dia pacifica Seem. & H. Wendl., the Miraguama palm (Kunth) Leon, MATERIALS AND METHODS and the endangered native Florida thatch palm Lodd. ex J. A. & J. H. (K. M. Grif- Source of Raoiella indica, Coconut, and Native Palms fiths, personal communication; Coile & Garland 2003). Foliage containing the RPM was collected from The establishment of R. indica in North Amer- heavily infested banana and coconut trees of un- ica has caused concerns about the economic im- known cultivars in Lake Worth, FL during 2008, pact of this new pest in palm nurseries, subtropi- placed into ice chests with ice packs, and brought cal agriculture, and natural and urban land- into the quarantine facility at the Department of scapes. The biology of R. indica was studied on co- Entomology and Nematology, University of Flor- conut in by Nagesha-Chandra & ida, Gainesville. The foliage samples were kept at Channabasavanna (1984) and on date palm in 21.5-23.8°C inside ice chests until RPM were used by Zaher et al. (1969), while studies on or- in tests. Potted coconut trees were purchased namental and landscape palms, bananas, or plan- from nurseries in southern Florida, tested for pes- tains have not been reported. The potential sus- ticide residues, and reared at the Department of ceptibility of native Florida palms to the RPM is Entomology and Nematology. Leaf discs used in of interest in the spread of the pest, as well as for the experiments were obtained from mature its effects in parks and natural areas. leaves. The native palms tested as suitable hosts A classical biological control program for were dwarf palmetto Sabal minor (Jacq.) Pers., Florida was initiated by identifying potentially saw palmetto Serenoa repens (Bartr.) Small, cab- effective predatory mites from areas where the bage palm Sabal palmetto (Walter) Lodd. ex RPM is endemic (Hoy et al. 2006). Predatory Schult., and needle palm Rhapidophyllum hystrix mites (Acari: Phytoseiidae) were imported from (Pursh). These native palm samples were col- and colonies were established in the lected in Gainesville, FL on the campus of the quarantine laboratory at the Department of En- University of Florida and at Kanahapa Botanical tomology and Nematology, University of Flor- Gardens from mature leaves that had not been ida, in Oct 2007. Colonies of the RPM and pred- treated with pesticides.

278 Florida Entomologist 92(2) June 2009

Raoiella indica Rearing on Banana Discs and Trees modification of the newly prepared banana discs, another bioassay was conducted with banana To verify that the RPM can be reared on ba- discs from leaves about 2-3 weeks old and held on nana leaf discs (leaves cut into pieces of specific the bioassay trays for 3 d before RPM were placed size), 4 banana varieties (Dwarf Puerto Rican on them. The experimental design was the same [plantain], Dwarf Cavendish, Dwarf Nino, and as the above experiment, except that only the cul- Gran Nain) obtained from Agri-Starts, Inc. (Apo- tivars Nang Phaya, Dwarf Green, and Glui Kai pka, FL) were potted into 3.8-L pots and allowed were tested, with coconut used as a control and 25 to produce 6-10 leaves before being evaluated, females were added. Development of the progeny with coconut leaf discs used as a positive control. was monitored until adulthood was reached. Leaf Discs 18 × 45 mm wide cut with a single-edge ra- discs were replaced after 3 weeks, when they be- zor blade from mature leaves were cleaned with a came yellow. Mites were moved from degraded to brush and inspected for undesirable predatory new leaf discs with a sable-hair brush (size 0000). mites or insects under a dissecting microscope. These bioassays were carried out at 27.8-33.1°C, Banana and coconut discs were placed on water- 43-100% RH during the oviposition period and at soaked cotton in a plastic tray (13 × 13 × 2.5 cm), 25.6-31.6°C, 51-100% RH during the developmen- with the abaxial surface of the leaves facing up. tal period of progeny, with both under a 16L:8D The cotton was kept wet for the duration of the photoperiod. bioassay by adding water periodically, and nar- To determine whether live banana trees could row paper strips (Kimwipe, Kimberly-Clark Cor- be used to rear the RPM under quarantine condi- poration, Roswell, GA) were placed along the edge tions, potted banana trees (varieties Glui Kai, of each leaf arena to reduce the likelihood of mites Nang Phaya, and Dwarf Green) ca. 20-30 cm tall running off or under the discs. Five young RPM were tested. Because of space limitations inside females, field collected from coconut trees (un- the quarantine room, a single potted coconut tree known cultivar), were placed on each disc; the was used as a control. Banana trees were pruned survivorship and the number of eggs laid were re- so that only a single leaf about 2-3 weeks old was corded under a dissecting microscope every 24 h used as the test arena. The leaves were cleaned for 7 d. Body length and dimensions of dark with a brush for undesirable insects and preda- patches on the dorsum of the body were consid- tory mites, and 20 young RPM females from field- ered to estimate the age of the females (Hoy et al. collected coconut leaves were placed on the abax- 2006). Twelve replicates were conducted by plac- ial surface of the leaves and left undisturbed for 7 ing 6 leaf discs for each treatment in 2 trays at d. Trees were placed into PVC-frame cages cov- 26.9-31.4°C, 56-100% RH, under a 16L:8D photo- ered with organdy cloth at 22.6-31.9°C, 42-73% period. RH, under a 16L:8D photoperiod. Live and dead Because the establishment of R. indica on ba- adults and the number of eggs and larvae on each nana leaf discs might be affected by the original leaf were recorded under a dissecting microscope. host of the mite, additional banana and plantain Each treatment was replicated 5 times on 2 dates. varieties were screened with young females col- If leaves were found that contained eggs or lar- lected from infested banana leaves (unknown va- vae, they were cut and placed on water-soaked riety) in Lake Worth, FL. Additional small ba- cotton for further observations of developmental nana and plantain trees (ca. 20 cm tall) were ob- success. tained from Agri-Starts, Inc. (Apopka, FL) and Survival analysis was estimated with the Dwarf Zan Moreno, Dwarf Green, Truly Tiny, PROC LIFEREG procedure (SAS Institute 2002). Musa sumatrana × Gran Nain (hybrid), Dwarf Pairwise comparisons were performed to evaluate Puerto Rican (plantain), Rose, Nang Phaya, Misi significant differences between survivorship pat- Luki, Manzano, Lady Finger, Glui Kai, and Ebun terns. The proportion of mites feeding, not feed- Musak varieties were tested, with coconut as a ing, or drowned/dead on each disc was compared positive control. Discs from leaves about 2-3 by logistic regression (PROC LOGISTIC, SAS In- weeks old were set up as described above, except stitute 2002). that each disc (ca. 70 × 70 mm wide) was placed in To evaluate the RPM oviposition rate, the a tray containing cotton saturated with water. mean number of eggs laid on each of the banana Ten young RPM females were placed on each disc or plantain discs was compared to the oviposition and left undisturbed for 11 d. Each female was rate on coconut discs with the Mann-Whitney U considered a replicate. The survivorship, the be- test (Proc NPAR1WAY, SAS Institute 2002). The havior (feeding, not feeding, drowned, or dead), treatment means were not compared with each and the number of eggs laid in each disc were re- other because we were interested in comparing corded under a dissecting microscope every 24 h, each to coconut only. Mortality rates of RPM eggs at 27.8-33.6°C, 44-100% RH, under a 16L:8D pho- and immatures were compared with the Fisher’s toperiod. exact test (PROC FREQ, SAS Institute 2002). In To investigate whether the female’s behavior the first bioassay, replicate discs of each treat- was determined by some chemical or physical ment were combined and analyzed as 1 data set.

Cocco & Hoy: Laboratory Rearing of the Red Palm Mite 279

Two-Choice Test for Host Preference on Selected Palms palmetto. The leaf discs were set up as for the two-choice test, except that the discs were of a sin- A two-choice test was conducted to determine gle leaf type. The survivorship, behavior (feeding, the host preference of RPM with coconut vs. coco- not feeding, drowned, or dead), and the number of nut, coconut vs. needle palm, coconut vs. saw pal- eggs laid by single young R. indica females on metto, coconut vs. cabbage palm, and coconut vs. each disc were recorded under a dissecting micro- dwarf palmetto. Discs 18 × 45 mm wide were cut scope every 24 h for 8 d. with a single-edge razor blade from mature leaves To determine whether immature stages were and hand washed with tap water and allowed to able to establish on these native palm species dry, which usually took 10-15 min. The 2 different from the eggs deposited by the females above, egg disc halves were sealed together by painting a 4- eclosion and survival of immatures were re- 5 mm wide stripe of melted paraffin wax with a corded. The entire experiment was conducted camel-hair brush on the abaxial (lower) surface with young RPM females collected from both in- (Hoy & Smilanick 1981). The joined leaf discs fested coconut and banana trees and was repli- were placed on water-soaked cotton in plastic cated 50 times on 2 dates. The bioassays with trays as for the previous tests. A single young RPM from coconut were carried out at 28.1- RPM female was placed on the midline paraffin 32.6°C, 50-100% RH; those with RPM from ba- stripe of each arena with a sable-hair brush (size nana at 28.8-33.4°C, 52-100% RH, both under a 0000) and allowed to move freely. The location 16L:8D photoperiod. (disc half type or paraffin wax stripe), the behav- Survivorship patterns were compared by the ior (feeding, not feeding, drowned, or dead), and PROC LIFEREG procedure (SAS Institute 2002). the number of eggs laid were recorded under a Pairwise comparisons were performed to evaluate dissecting microscope after 48 h. Mites were significant differences between treatments. The checked under a dissecting microscope after 24 h proportion of mites feeding, not feeding, or to confirm the survival of each female and to de- drowned/dead on each disc was compared by lo- termine whether females had moved from the gistic regression (PROC LOGISTIC, SAS Insti- paraffin midline. RPM females were touched gen- tute 2002). The mean number of eggs laid during tly with a sable-hair brush and considered alive if 8 d on each palm species was compared to that on they moved or walked away, while dead females coconut discs Mann-Whitney U test (Proc were removed and replaced with live adults. The NPAR1WAY, SAS Institute 2002). The percent- experiment was replicated 35 times by placing 5 ages of egg, larval, and protonymphal mortality arenas for each type of two-choice leaf disc in 7 were analyzed with exact logistic regression trays. Two bioassays were conducted with RPM (PROC LOGISTIC, SAS Institute 2002). females collected either from coconut or banana trees in the field in order to investigate whether Survival of R. indica on Needle Palm Leaf Discs the original host plant affected host choice. The experiments were conducted at 28.1-34.6°C, 52- To determine whether R. indica could estab- 100% RH when mites from coconut were used, lish on needle palm discs, the survival of RPM im- and at 28.5-33.4°C, 42-100% RH when mites from matures on that host plant was investigated and bananas were tested, both under a 16L:8D photo- compared to survival on coconut discs. The leaf period. Temperature and RH were recorded with discs were set up as described above, except that a Traceable® Digital Thermometer (Fisher Elec- they were 25 × 90 mm wide and were not washed tronics, Pittsburgh, PA). but cleaned with a brush to preserve the cuticle Exact logistic regression (PROC LOGISTIC, characteristics. Fifteen young RPM females were SAS Institute 2002) was used to analyze R. indica sampled from field-collected coconut leaves and behavioral response (host choice) to host plants placed on the leaf discs for 6 d and then removed. because some observations had zero values or Dead or drowned females were replaced every 24 separation of the data set occurred (Heinze & h to maximize the number of eggs laid on coconut Ploner 2003). The number of eggs laid by RPM fe- and needle palm leaf discs. The number of eggs males on discs of the same arena was compared laid, the percentage of egg eclosion, and the sur- with the Mann-Whitney U test (Proc NPAR1WAY, vival rate of RPM immatures were recorded every SAS Institute 2002). 24 h until adulthood was reached. The mean egg incubation time was estimated per each disc as Survival and Reproduction of Females in No-choice MIT = χ– egg eclosion date – χ– egg oviposition Tests on Selected Ornamental and Native Palms date (1) To determine whether RPM females were able where MIT is the Mean Incubation Time, the to establish and oviposit on selected native palms mean egg eclosion date is the mean between the of Florida, the behavior of single young females in first and last day of egg eclosion, and the mean single leaf discs was observed on coconut, needle egg oviposition date is the mean between the first palm, saw palmetto, cabbage palm, and dwarf and the last day of egg oviposition. The mean de-

280 Florida Entomologist 92(2) June 2009

velopment time from larva to adult was estimated (χ2 = 166.28; df = 4; P < 0.0001). Survivorship of per each disc as RPM females on coconut leaf discs after 7 d was 52%, significantly different than the survival on MDT = χ– adult emergence date – χ– egg eclo- Dwarf Puerto Rican, Dwarf Cavendish, Dwarf sion date (2) Nino, or Gran Nain discs (all pairwise compari- where MDT is the Mean Development Time, the sons: P < 0.0001). The survivorship pattern of mean adult emergence date is the mean between RPM females on Dwarf Nino and Gran Nain leaf the first and last adult emergence, and the mean discs was not statistically different (χ2 = 0.30; df = egg eclosion date is the mean between the first 1; P = 0.5831). Dwarf Cavendish (banana variety)

and last day of egg eclosion. The emerging F1 fe- and Puerto Rican (plantain variety) leaf discs males were examined every 24 h to verify were significantly less suitable than the other whether they laid eggs or not. Leaf discs were re- hosts tested. placed every 3-4 weeks, when discs appeared de- During the 7-day bioassay, 60 RPM females graded. Mites were transferred from aged to new laid a total of 261 eggs on coconut leaf discs, while leaf discs with a sable-hair brush. The bioassay surviving females laid a total of 6, 3, 32, and 42 was replicated 8 times, at 27.8-32.9°C, 48-72% RH eggs on Dwarf Puerto Rican, Dwarf Cavendish, during the oviposition period and at 25.6-29.9°C, Gran Nain, and Dwarf Nino discs, respectively 56-100% RH during the developmental period, (data not shown). The pairwise comparisons be- both under a 16L:8D photoperiod. tween the mean oviposition rate of the RPM on The mean egg incubation time, and the mean coconut discs (0.76 eggs/female/d) showed signif- development time from larva to adult were ana- icant differences from these on Dwarf Puerto lyzed with the Mann-Whitney U test (Proc Rican (0.17 eggs/female/d) (P = 0.0054), Dwarf NPAR1WAY, SAS Institute 2002) (Lee 1992). Cavendish (0.05 eggs/female/d) (P = 0.0033), Mortalities of eggs and immatures were evalu- Gran Nain (0.25 eggs/female/d) (P = 0.0037), and ated with one-way ANOVA in Proc GLIMMIX Dwarf Nino (0.27 eggs/female/d) (P = 0.0068) leaf (SAS Institute 2002). discs. When RPM females that were field collected RESULTS AND DISCUSSION from banana trees were tested on 12 different ba- nana and plantain leaf discs, significant differ- Raoiella indica Rearing on Banana Discs and Trees ences in survivorship were observed among the treatments (χ2 = 108.85; df = 4; P < 0.0001) During the first experiment, RPM females did (Table 1). The banana variety Misi Luki appeared not establish on the 4 varieties of banana or plan- to be the least suitable host, with all RPM females tain leaf discs, but they settled down on coconut dying or running off the discs by the second day of discs (Fig. 1). There were significant differences in the bioassay. After 4 d, 100% mortality was ob- survival of RPM females on different leaf discs served on Truly Tiny, Dwarf Puerto Rican, Rose,

Fig. 1. Survivorship of R. indica females collected from coconut on different banana and plantain leaf discs un- der quarantine conditions (n = 60 for each plant type). Treatments followed by the same letter are not significantly different (P < 0.05).

Cocco & Hoy: Laboratory Rearing of the Red Palm Mite 281

TABLE 1. SURVIVORSHIP, BEHAVIOR AND MEAN OVIPOSITION RATE OVER 11 D OF R. INDICA FEMALES COLLECTED FROM BANANA ON SELECTED HOST PLANT DISCS UNDER NO-CHOICE QUARANTINE CONDITIONS.

Female behavior (%)d Comparisons of Mean no. of survivorship over No. of Not Drowned eggs//d Host planta 11 db observationsc Feeding feeding or dead (±SE)e

Coconut a 95 94 a 2 b 4 c 0.97 ± 0.18 Glui Kai b 61 61 b 23 a 16 b 0.15 ± 0.05 * Dwarf Green c 34 38 cd 32 a 30 ab 0.23 ± 0.10 * Nang Phaya c 31 49 bc 19 a 32 ab 0.26 ± 0.22 * M. sumatrana × Gran Nain cd 25 32 cd 28 a 40 ab 0.07 ± 0.05 * Manzano cd 25 20 d 40 a 40 ab 0.03 ± 0.03 * Rose cde 21 38 cd 14 a 48 a 0.08 ± 0.08 * Zan Moreno cde 17 29 cd 12 ab 59 a 0.22 ± 0.16 * Ebun Musak cde 21 28 cd 24 a 48 a 0.23 ± 0.19 * Truly Tiny de 17 23 cd 18 a 59 a 0.13 ± 0.13 * Puerto Rican e 13 15 d 8 ab 77 a 0 * Lady Finger e 15 26 cd 7 ab 67 a 0.75 ± 0.25 ns Misi Luki e 15 26 cd 7 ab 67 a 0.30 ± 0.30 ns

aLaboratory conditions: 27.8-33.6°C, 44-100% RH, under a 16L:8D photoperiod. Number of females tested for each plant type = 10. bSignificant differences among survivorship patterns compared with PROC LIFEREG, treatments followed by the same letter within a column are not significantly different (P < 0.05). cDiscrepancies in number of observations (potentially 10 × 11 d = 110) are due to the different female survival rates. dSignificant differences compared with PROC LOGISTIC, treatments followed by the same letter within a column are not sig- nificantly different (P < 0.05). eSignificant differences between coconut and each host plant compared with Mann-Whitney U test (PROC NPAR1WAY), treat- ment means with * are significantly different compared to coconut (P < 0.05). and Lady Finger leaf discs, while on Dwarf Green Nain, Manzano, Rose, Dwarf Zan Moreno, Ebun and Ebun Musak the same mortality rate was ob- Musak, Truly Tiny, Dwarf Puerto Rican, Misi served after 5 d. On Dwarf Zan Moreno, Nang Luki, and Lady Finger, but the differences were Phaya, and Manzano leaf discs, no live female not significant (Table 1). was observed after 6 d, while the longest survival The oviposition rate of RPM females on coco- among banana varieties was observed on Glui Kai nut was 0.97 eggs/female/d, which was signifi- leaf discs (11 d). By contrast, RPM females on co- cantly higher than on Glui Kai, Dwarf Green, conut discs exhibited 40% mortality after 11 d. Nang Phaya, M. sumatrana × Gran Nain, Puerto During the leaf disc bioassay, the Glui Kai variety Rican, Manzano, Rose, Zan Moreno, Ebun Musak, appeared to be the most suitable banana host for Truly Tiny, and Puerto Rican leaf discs (all pair- the RPM (Table 1). Survivorship patterns of RPM wise comparisons were between the oviposition females on Dwarf Green and Nang Phaya discs rate on each banana or plantain leaf disc and that were not different than on Musa sumatrana × on coconut discs: P < 0.05) (Table 1). Raoiella in- Gran Nain, Manzano, Rose, Dwarf Zan Moreno, dica females laid 0.75 and 0.30 eggs/female/d on and Ebun Musak, while they were statistically Lady Finger and Misi Luki leaf discs, respectively, different from the survival rate on Truly Tiny, which were not significantly different from that Dwarf Puerto Rican, Misi Luki, and Lady Finger on coconut discs. Only 15 behavior observations leaf discs (Table 1). were made on those discs because RPM females Observations on feeding behavior showed that survived only 4 and 2 d, respectively, suggesting RPM females fed significantly more frequently on that females laid eggs immediately after being coconut than on banana or plantain leaf discs (P < placed on the discs and then ran off the discs. 0.0001) (Table 1). Females of R. indica were ob- When RPM females were tested on 3-d-old served feeding on Glui Kai discs in 61% of the ob- Dwarf Green, Glui Kai, Nang Phaya, and coconut servations, significantly more than on Dwarf leaf discs, the 4 treatments exhibited significantly Green, Musa sumatrana × Gran Nain, Manzano, different survivorship patterns from one another (F Dwarf Zan Moreno, Ebun Musak, Truly Tiny, = 70.79; df = 3; P < 0.0001) (Table 2). No live RPM fe- Dwarf Puerto Rican, Misi Luki, and Lady Finger males were observed on Nang Phaya and Dwarf leaf discs (P < 0.05). The proportion of RPM fe- Green after 5 and 7 d, respectively, while 100% mor- males feeding on the host ranged from 15 to 38% tality was observed on Glui Kai discs after 11 d. on Dwarf Green, Rose, Musa sumatrana × Gran Consistent with the previous bioassay, female sur- 282 Florida Entomologist 92(2) June 2009

TABLE 2. SURVIVORSHIP AND OVIPOSITION RATE OF R. INDICA OVER 11 D, MORTALITY OF EGGS AND IMMATURES AND SUCCESSFUL DEVELOPMENT TO ADULT ON DIFFERENT 3-D-OLD DISCS UNDER NO-CHOICE QUAR- ANTINE CONDITIONS.

Mortality of R. indica (%)d Successful Comparisons of Mean no. of development to Host planta survivorship over 11db eggs//d (±SE)c Eggsns Immatures* adult (%)

Coconut a 0.93 ± 0.12 9 57 40 Glui Kai b 0.26 ± 0.06 * 5 69 30 Dwarf Green c 0.29 ± 0.11 * 4 77 22 Nang Phaya d 0.13 ± 0.06 * 0 100 0

aLaboratory conditions: 27.8-33.1°C, 43-100% RH (oviposition period); 25.6-31.6°C, 51-100% RH (developmental period), both un- der a 16L:8D photoperiod. Number of females tested for each plant type = 25. bSignificant differences among survivorship patterns compared with PROC LIFEREG, treatments followed by the same letter within a column are not significantly different (P < 0.05). cSignificant differences between coconut and each host plant compared with Mann-Whitney U test (PROC NPAR1WAY), treat- ment means with * are significantly different compared to coconut (P < 0.005). dTreatments were compared with the Fisher’s exact test, ns = no differences among treatments; * = significant differences among treatments (P < 0.05). vival on Glui Kai discs was significantly higher than trees. After 7 d, no females survived and a total of these on Dwarf Green or Nang Phaya. At the end of only 17, 10, and 1 eggs were observed on Glui Kai, the experiment, RPM females on coconut discs ex- Dwarf Green, and Nang Phaya leaves, respec- perienced 36% mortality. The mean fecundity of tively, corresponding to mean oviposition rates of RPM females on coconut leaf discs (0.93 eggs/fe- 0.17, 0.10, and 0.01 eggs/female/7 d, respectively male/d) differed significantly from these of females (Table 3). In the same climatic conditions, RPM on Glui Kai, Dwarf Green, or Nang Phaya discs females established and laid eggs on coconut (0.26, 0.29, and 0.13 eggs/female/d, respectively) leaves. A coconut leaf disc of ca. 25 cm2 sampled (Table 2). All the pairwise comparisons between the randomly revealed 36 R. indica females alive and oviposition rate on coconut discs and on banana 154 eggs, with a mean fecundity of 4.3 eggs/fe- discs indicated a significant difference with P < male/7 d, and only 1 dead (3% mortality) (data not 0.05. The R. indica eggs experienced 0-9% mortality shown). Mortality rates of RPM eggs on banana during the bioassay, but differences were not signif- leaves ranged from 0 (Nang Phaya) to 50% (Glui icant (P = 0.8576) (Table 2). Mortality of RPM im- Kai), while larvae experienced 75, 0, and 100% matures was significantly different among treat- mortality after 7 d on Glui Kai, Dwarf Green, and ments (Fisher’s exact test: P = 0.0381), ranging from Nang Phaya leaves, respectively (Table 3). Leaves 57% on coconut to 100% on Nang Phaya leaf discs. with eggs or larvae were cut and placed on water- The rate of successful development from egg to soaked cotton, and subsequent observations indi- adult on coconut, Glui Kai, Dwarf Green, and Nang cated that all larvae died within 4 d and failed to Phaya discs was 40, 30, 22, and 0%, respectively molt to the protonymphal stage (Table 3). (Table 2). The emerged RPM females did not deposit eggs on Glui Kai, Dwarf Green, or Nang Phaya discs Two-Choice Test for Host Preference on Selected Palms and died within 7 d, while on coconut discs 88 RPM females established and laid 97 eggs over 7 d (data Raoiella indica females did not exhibit a pref- not shown). erence between needle palm or coconut leaf discs RPM females also failed to establish on potted (Table 4, test A1: exact P = 1.0000; test B1: exact Glui Kai, Nang Phaya, and Dwarf Green banana p = 0.8506). The proportion of females feeding on

TABLE 3. OVIPOSITION RATE AND MORTALITY OF ADULTS, EGGS AND LARVAE OF R. INDICA OVER 7 D ON DIFFERENT BA- NANA TREES UNDER QUARANTINE CONDITIONS.

Mortality of R. indica (%) Total no. Mean no. % molting from Host planta eggs/20/ 7 d of eggs//7 d (±SE) Adults Eggs Larvae larvae to protonymphs

Glui Kai 17 0.17 ± 0.09 100 6 75 0 Dwarf Green 10 0.10 ± 0.05 100 50 0 0 Nang Phaya 1 0.01 ± 0.01 100 0 100 0

aLaboratory conditions: 22.6-31.9°C, 42-73% RH, under a 16L:8D photoperiod. Number of females in each treatment = 20. In the same climatic conditions, RPM females on coconut leaves exhibited 3% mortality and a mean fecundity of 4.3 eggs/female/7 d. Cocco & Hoy: Laboratory Rearing of the Red Palm Mite 283

TABLE 4. BEHAVIOR AND OVIPOSITION RATE OF R. INDICA FEMALES OVER 2 D COLLECTED FROM COCONUT (A) AND BA- NANA (B) IN 2-CHOICE LEAF DISC BIOASSAYS UNDER QUARANTINE CONDITIONS.

Female behavior (%)c mean no. Females observed Drowned of egg//48 h Treatmenta on each half (%)bc Feeding Not feeding or dead (±SE)d

A Mites collected from coconut 1) Coconut vs 49 a 88 a 6 a 6 a 1.4 ± 0.3 a Needle palm 46 a 100 a 0 a 0 a 0.9 ± 0.3 a 2) Coconut vs 66 a 91 a 0 b 9 a 1.8 ± 0.3 a

Saw palmetto 9 b 0 b 67 a 33 a 0 b 3) Coconut vs 40 a 93 a 0 b 7 b 1.6 ± 0.3 a

Cabbage palm 34 a 0 b 42 a 58 a 0 b 4) Coconut vs 60 a 95 a 0 b 5 b 0.9 ± 0.2 a

Dwarf palmetto 26 b 0 b 33 a 67 a 0 b 5) Coconut vs 46 a 94 a 0 a 6 a 1.5 ± 0.3 a Coconut 49 a 94 a 0 a 6 a 2.1 ± 0.3 a B Mites collected from banana 1) Coconut vs 37 a 100 a 0 a 0 a 1.0 ± 0.2 a Needle palm 43 a 87 a 0 a 13 a 0.9 ± 0.3 a 2) Coconut vs 66 a 91 a 4 a 4 b 1.2 ± 0.3 a

Saw palmetto 29 b 0 b 10 a 90 a 0 b 3) Coconut vs 66 a 100 a 0 a 0 b 1.0 ± 0.2 a

Cabbage palm 14 b 0 b 0 a 100 a 0 b 4) Coconut vs 60 a 100 a 0 a 0 b 1.2 ± 0.2 a

Dwarf palmetto 14 b 0 b 0 a 100 a 0 b 5) Coconut vs 46 a 88 a 0 a 12 a 1.4 ± 0.3 a Coconut 40 a 93 a 0 a 7 a 1.2 ± 0.3 a

aLaboratory conditions: (A) 28.1-34.6°C, RH 52-100%; (B) 28.5-33.4°C, RH 42-100%, both under 16L:8D photoperiod. Number of females observed after 48 h for each bioassay = 35. bDiscrepancies in the percentage of females on tested halves are because some females were found on the midline. cSignificant differences compared with PROC LOGISTIC, treatments followed by the same letter within a column for each bio- assay are not significantly different (exact P < 0.05). dSignificant differences compared by the Mann-Whitney U test (PROC NPAR1WAY), means followed by the same letter within a column for each bioassay are not significantly different (P < 0.05). coconut or needle palm discs after 48 h during tests vations after 24 and 48 h revealed that mites did not A1 and B1 ranged from 87 to 100%, but the differ- change their position after their original choice, per- ences were not significant. RPM females appeared haps due to the width of the paraffin seal (4-5 mm). to prefer coconut over saw palmetto (test A2: exact P RPM oviposition rates on coconut and needle < 0.0001; test B2: exact p = 0.0351) or dwarf pal- palm during the 48-h test were not significantly dif- metto (test A4: exact P = 0.0428; test B4: exact p = ferent, whether females were collected from coconut 0.0025). No mites were observed feeding on saw pal- or banana (Table 4, tests A1: χ2 = 1.6770; df = 1; p = metto or dwarf palmetto leaf discs during the 48-h 0.1953; B1: χ2 = 0.4678; df = 1; p = 0.4940). However, experiments. Unexpectedly, RPM females did not no eggs were laid by females on saw palmetto, cab- show a preference between coconut and cabbage bage palm, or dwarf palmetto disc halves (Tests A2, palm leaf discs in test A3 (exact p = 0.8450), while A3, A4, B2, B3, B4), while RPM females on coconut there was a significant difference between these halves of the same test arenas produced 0.9 to 1.8 host plants in test B3 (exact p = 0.009). However, no eggs/female /48 h. mites were detected feeding on cabbage palm discs during experiments A3 and B3, while all live fe- Survival and Reproduction of Females in No-choice males on the coconut halves of the test arenas ap- Tests on Selected Ornamental and Native Palms peared established. During the two-choice tests, no RPM female was observed feeding on saw palmetto, The native saw palmetto, cabbage palm, and cabbage palm, or dwarf palmetto leaf discs. Obser- dwarf palmetto do not seem to be palatable hosts 284 Florida Entomologist 92(2) June 2009 for the RPM under quarantine conditions cantly different in both experiments. Experi- (Table 5). Despite the fact that adult females from ments A and B (Table 5) were performed using the field-collected banana or coconut foliage were mites collected from infested coconut and banana assigned randomly to the test leaf discs, there trees on two dates, so no statistical analysis were were significant differences in survivorship over 8 performed to compare the two survivorship d (Table 5A: χ2 = 218.2219; df = 4; P < 0.0001; Ta- curves. However, RPM females collected from co- ble 5B: χ2 = 241.0365; df = 4; P < 0.0001). Coconut conut appeared to survive longer than females and needle palm discs appeared to be the most collected from banana trees on coconut (90 and suitable hosts for RPM females, while they did 55%, respectively) and needle palm (76 and 34%, not establish on saw palmetto, cabbage palm, or respectively) leaf discs (data not shown). dwarf palmetto discs. Survivorship of R. indica fe- Behavior observations during the no-choice males collected from coconut trees on needle palm test indicated that coconut was the better host for and coconut leaf discs after 8 d were 76 and 90%, the RPM females (Table 5). Significantly more R. respectively, but the pairwise comparison was not indica females were observed feeding on coconut significantly different (χ2 = 3.68; df = 1; P = discs than on needle palm, saw palmetto, cabbage 0.0550) (Table 5A). On saw palmetto discs, RPM palm, or dwarf palmetto discs in both experi- females survived significantly longer than on cab- ments (P < 0.0001 for both) (Table 5A, B). How- bage palm (χ2 = 17.83; df = 1; P < 0.0001) or dwarf ever, needle palm discs appeared to be palatable palmetto discs (χ2 = 15.19; df = 1; P < 0.0001) (Ta- to RPM females, which were observed feeding on ble 5A). When RPM females collected from ba- that host 72 and 59% of the observations (P < nana were used, the survivorship on coconut and 0.0001, Table 5A, B). Red palm mite females were needle palm discs were 52 and 34%, respectively, observed feeding significantly less frequently on showing a marginally significant difference (χ2 = needle palm than on coconut leaf discs after 8 d 3.96; df = 1; P = 0.0467) (Table 5B). The survivor- (Table 5), while those differences in feeding be- ship pattern of R. indica females collected from havior were not significant after 2 d (Table 4), infested banana trees on saw palmetto was signif- suggesting that longer observations are more re- icantly different than that on cabbage palm (χ2 = liable to determine the palatability of the host 6.93; df = 1; P = 0.0085), while there was no differ- plant. ence in female survival on saw palmetto and Only 1 to 2% of the observations revealed R. in- dwarf palmetto discs (χ2 = 2.08; df = 1; P = 0.1491). dica feeding on saw palmetto, cabbage palm, or Survivorship patterns of R. indica on cabbage dwarf palmetto discs, whether using RPM fe- palm and dwarf palmetto discs were not signifi- males collected from coconut or banana trees, and

TABLE 5. SURVIVORSHIP AND BEHAVIOR OF R. INDICA FEMALES COLLECTED FROM COCONUT (A) AND BANANA (B) ON SELECTED HOST PLANT DISCS UNDER NO-CHOICE QUARANTINE CONDITIONS OVER 8 D.

Female behavior (%)d

Comparisons of No. Drowned or Host plant a survivorship over 8 db observationsc Feeding Not feeding dead

A Mites collected from coconut Coconut a 387 95 a 4 c 1 b Needle palm a 343 72 b 25 b 3 b Saw palmetto b 138 2 c 62 a 36 a Cabbage palm c 90 1 c 43 a 56 a Dwarf palmetto c 92 1 c 45 a 54 a B Mites collected from banana Coconut a 301 85 a 7 c 8 b Needle palm b 259 59 b 28 b 13 b Saw palmetto c 100 2 c 48 a 50 a Cabbage palm d 77 1 c 34 ab 65 a Dwarf palmetto cd 86 1 c 41 ab 58 a

aLaboratory conditions: (A) 28.1-32.6°C, 50-100% RH; (B) 28.8-33.4°C, 52-100% RH, both under a 16L:8D photoperiod. Number of females observed on each host plant = 50 for 8 d. bSignificant differences among survivorship patterns compared with PROC LIFEREG, treatments followed by the same letter within a column in each experiment are not significantly different (P < 0.05). cDiscrepancies in number of observations (potentially 50 × 8 d = 400) are due to the different female survival rates. dSignificant differences compared with PROC LOGISTIC, treatments followed by the same letter within a column are not sig- nificantly different (P < 0.05). Cocco & Hoy: Laboratory Rearing of the Red Palm Mite 285 there were no significant differences in RPM feed- gesting that coconut could be a more favorable ing behavior on these discs (P > 0.05). host than banana in the field. The fecundity of During the 8 d of the experiments, 50 R. indica RPM females on needle palm discs was signifi- females collected from coconut trees laid a total of cantly lower than coconut discs after 8 d (Tables 360 eggs on coconut leaf discs, with an oviposition 6A, B) while the oviposition rate was not different rate of 0.92 eggs/female/d (Table 6A). RPM fe- on coconut and needle palm discs after 2 d males from the same source laid a total 104 eggs (Table 4), suggesting that RPM females laid most on needle palm leaf discs, corresponding to an ovi- eggs on needle palm discs immediately after position rate of 0.28 eggs/female/d, while females transfer, while the oviposition rate on coconut laid a total of only 1, 2, and 2 eggs (0.01 eggs/fe- discs was more constant. male/d) on dwarf palmetto, saw palmetto, and Mortality of eggs on coconut discs (11%) dif- cabbage palm, respectively, over 8 d. The fecun- fered significantly from the egg mortality ob- dity on coconut discs was significantly higher served on needle palm discs (24%) (Table 6A, than on needle palm (Mann-Whitney U test, P < exact P = 0.0014). Mortality data of eggs from 0.0001), saw palmetto (Mann-Whitney U test, P < saw palmetto, cabbage palm, and dwarf pal- 0.0001), cabbage palm (Mann-Whitney U test, P < metto was excluded from the statistical analy- 0.0001), or dwarf palmetto discs (all pairwise sis because of the low number of eggs laid. Lar- comparisons between coconut vs. each native vae that hatched on coconut discs experienced palm with Mann-Whitney U test: P < 0.0001). 11% mortality, which was significantly lower Likewise, when RPM females collected from ba- than the larval mortality on needle palm discs nana trees were used, their oviposition rate on co- (81%) (exact P < 0.0001). Mortality of proto- conut discs (0.49 eggs/female/d) was significantly nymphs on coconut discs was 21%, while all higher than on other hosts (all pairwise compari- protonymphs on needle palm discs died before sons: P < 0.0001). On needle palm discs females molting to the deutonymphal stage (exact P < laid a total of 36 eggs, at a rate of 0.11 egg/female/ 0.0001). Mortality rates of eggs laid by RPM fe- d, while on saw palmetto discs only 2 eggs were males from banana trees on coconut and needle observed (0.01 egg/female/d) (Table 6B). No eggs palm discs were significantly different (8 and were deposited on cabbage palm and dwarf pal- 36%, respectively) (Table 6B, exact P < 0.0001). metto discs. RPM females field collected from co- RPM larvae developed on coconut discs experi- conut trees exhibited a higher fecundity than fe- enced 63% mortality, while no larvae molted males sampled from banana trees (0.92 and 0.49 successfully to the protonymphal stage on nee- eggs/female/d, respectively) (Table 6A, B), sug- dle palm discs (exact P = 0.0007). RPM females

TABLE 6. MEAN FECUNDITY OVER 8 D OF R. INDICA FEMALES COLLECTED FROM COCONUT (A) AND BANANA (B) AND MORTALITY OF EGGS AND IMMATURES ON SELECTED HOST PLANT DISCS UNDER NO-CHOICE QUARANTINE CON- DITIONS OVER 24 D.

Mortality of R. indica (%)c Mean no. Host planta of eggs//d (±SE)b Eggs Larvae Protonymphs

A Mites collected from coconut Coconut 0.92 ± 0.04 11 b 33 b 21 b Needle palm 0.28 ± 0.03 * 24 a 81 a 100 a Saw palmetto 0.01 ± 0.01 * — — — Cabbage palm 0.01 ± 0.01 * — — — Dwarf palmetto 0.01 ± 0.01 * — — — B Mites collected from banana Coconut 0.49 ± 0.06 8 b 37 b 29 Needle palm 0.11 ± 0.02 * 36 a 100 a — Saw palmetto 0.01 ± 0.01 * — — — Cabbage palm 0 — — — Dwarf palmetto 0 — — —

aLaboratory conditions: (A) 28.1-32.6°C, 50-100% RH; (B) 28.8-33.4°C, 52-100% RH, both under a 16L:8D photoperiod. Number of females observed on each host plant = 50 for 8 d. bSignificant differences between coconut and each host plant compared with Mann-Whitney U test (PROC NPAR1WAY), treat- ment means with * are significantly different compared to coconut (P < 0.0001). cSignificant differences compared with PROC LOGISTIC, treatments followed by the same letter within a column are not signif- icantly different (exact P < 0.05). Mortality of eggs and larvae from saw palmetto, cabbage palm, and dwarf palmetto were excluded from the analysis because of the low number of eggs laid. 286 Florida Entomologist 92(2) June 2009 collected from coconut trees survived longer, ex- made mite counts difficult and observations on co- hibited an higher oviposition rate, and were ob- conut discs were stopped. However, on needle served feeding more often on coconut and nee- palm discs, observations were stopped 64 d after dle palm discs than females collected from ba- the beginning of the bioassay, and a total of only nana trees (Tables 5 and 6), perhaps due to the 49 eggs were scored. different age of leaves tested or to the lower suitability of banana for the RPM. CONCLUSIONS

Survival of R. indica on Needle Palm Leaf Discs The RPM established on coconut leaf discs and potted trees, and small colonies have been main- During the 6-d assay, a total of 135 and 155 fe- tained for many generations, while no stable col- males were tested on coconut and needle palm ony has been obtained on banana or plantain discs, respectively. Thirty five females were re- discs or potted banana trees. Likewise, no RPM placed on needle palm because they died or ran off females survived on the ornamental and native the discs, while 15 females were replaced on coco- palm discs tested, except on needle palm discs, nut discs for the same reason. Despite the lower where the RPM completed a generation but expe- number of females tested on coconut, a total of rienced high mortality and a long development 648 eggs were laid on coconut discs and 365 on time. needle palm. Mortality of eggs laid on coconut It is unclear whether R. indica can actually discs was 3%, which was significantly lower than feed, reproduce, and develop within a normal egg mortality (7%) on needle palm discs (F = time period on all plants listed in Table 8 because 30.67; df = 1, 14; P < 0.0001). During development information about which RPM life stage was ob- to adulthood, RPM immatures feeding on coconut served on these plants was not always provided discs exhibited significantly lower mortality (Fletchmann & Etienne 2004; Kane & Ochoa (67%) than immatures growing on needle palm 2006; Mendonça et al. 2006; Welbourn 2006). (84%) (F = 33.87; df = 1, 14; P < 0.0001) (Table 7). Pedigo (1996, p. 425) defines a host plant as “Suf- Although the determination of the exact develop- ficiency of the plant as a host is finally determined ment time of R. indica was beyond goal of the ex- during feeding. If nutrients are adequate and no periment, the Mean Incubation Time and the toxicity occurs, the insect completes development Mean Development Time were assessed. The within a normal time period and becomes an mean Incubation Time ranged from 5.9 to 6.2 d on adult. Also sufficiency is indicated in normal needle palm and coconut, respectively, but the dif- adult longevity and fecundity”. It is possible that ference was not significant (χ2 = 1.7340; df = 1; P the RPM was dispersed by wind currents to some = 0.1879) (Table 7). The development time from of these plants located beneath palm canopies, larva to adult on coconut discs averaged 12.1 d, and it is possible that gravid females could de- which was significantly lower than the Mean De- posit a few eggs on these temporary hosts, but the velopment Time (25.9 d) on needle palm discs (χ2 establishment of a multigenerational colony has = 10.7299; df = 1; P = 0.0011). A total of 153 and not always been documented. 35 female progeny developed successfully on coco- Unknown varieties of bananas have been re- nut and needle palm discs, respectively. Discs ported to be suitable hosts for the RPM in Florida were examined every 24 h to verify the presence (A. Cocco, personal observation), while in the

of F2 eggs. On coconut discs, 21 d after the begin- Eastern Caribbean significant multigenerational ning of the experiment, a total 961 eggs were infestations have been observed on the most scored, with a 30% daily rate of increase which widely grown banana (Dwarf Cavendish, Giant

TABLE 7. OVIPOSITION RATE OVER 6 D, MORTALITY OF EGGS AND IMMATURES, AND DEVELOPMENT TIME OF R. INDICA ON COCONUT AND NEEDLE PALM DISCS UNDER NO-CHOICE QUARANTINE CONDITIONS.

Mortality of R. indica (%)b Mean Mean Development Total no. of Total no. of Incubation Time larva to Treatmenta tested on 6 d eggs/6 d Eggs Immatures Time (d ± SE)c adult (d ± SE)c

Coconut 135 648 3 ± 1 b 67 ± 6 b 6.2 ± 0.1 a 12.1 ± 0.2 b Needle palm 155 365 7 ± 3 a 84 ± 4 a 5.9 ± 0.1 a 25.9 ± 0.8 a

aLaboratory conditions: 27.8-32.9°C, 48-72% RH (oviposition period); 25.6-29.9°C, 56-100% RH (developmental period), both un- der a 16L:8D photoperiod. Initial number of females for each of 8 replications = 15. bTreatment means were compared with PROC GLIMMIX, means with the same letter within a column are not significantly dif- ferent. cSignificant differences compared by the Mann-Whitney U test (PROC NPAR1WAY); means followed by the same letter within a column for each bioassay are not significantly different (P < 0.05). Cocco & Hoy: Laboratory Rearing of the Red Palm Mite 287 b ony has not always been documented. ony has not always Griffiths, personal communication Griffiths, Mitrofanov & Strunkova (1979) & Etienne (2004) Fletchmann & Baker (1958) Pritchard K. Griffiths, personal communication Griffiths, K. Kane et al. (2005) Kane et al. ) Chrysalidocarpus ) . um. & H. Perrier & H. um. personal communication Griffiths, K. J eitchia . V . a in press (F. Muell.) H. Wendl. & DrudeWendl. Muell.) H. (F. K. (H. Wendl. ex H .J.Veitch) H. Wendl. ex Hook. F. ex Hook. Wendl. H. ex H .J.Veitch) Wendl. (H. Etienne & Fletchmann (2006) (Kunth) Becc H. Wendl. ?Wendl. H. personal observation Cocco, A. H. Wendl. ex Sarg.Wendl. H. (2006) Welbourn Seem. & H. Wendl. Wendl. & H. Seem. Etienne & Fletchmann (2006) L. personal communication Griffiths, K. (Mart.) Becc. (2006)* Welbourn (Jacq.) L. H. Bailey H. L. (Jacq.) personal observation Cocco, A. C. (R.Br.) Blume(R.Br.) personal communication Griffiths, K. INDICA (Grises. & H. Wendl.) & H. (Grises. (2006)* Welbourn

(Bory) H. Wendl. & Drude ex Scheff.Wendl. (Bory) H. Moutia (1958) (Kunth) H. A. Wendl. A. (Kunth) H. personal communication Griffiths, K. B. hort. ex Chabaud hort. Etienne & Fletchmann (2006) Mart. (2006)* Welbourn L. Sayed (1942) Sayed L. (Jacq.) R. Br. R. (Jacq.) personal communication Griffiths, K. acq. (2006)* Welbourn Hildebr. & Wendl. & Hildebr. (2006) Welbourn O’Brien (2006) Welbourn (Becc.) Becc. (= Becc. (Becc.) J Jacq. (2006) Welbourn (H. Wendl.) Beentje & J. Dransf. (= Dransf. Beentje & J. Wendl.) (H. H. Wendl. Wendl. H. Etienne & Fletchmann (2006) (Jum.) Beentje & J. Dransf. Beentje & J. (Jum.) (2006) Welbourn L. Hirst (1924) Hirst L. (Mart.) Becc. personal communication Griffiths, K. spp. (2006) Welbourn L. Nagesha-Chandra & Channabasavanna (1984) Lour. Etienne & Fletchmann (2006) sp. personal observation Cocco, A. AOIELLA R

sp. sp. (2005) Kane et al. OF

sp. sp. SPECIES nobilis Bismarckia Acer Acoelorraphe wrightii Adonidia merrilli caryotifolia Aiphanes alexandrae Archontophoenix Bactris plumeriana Beccariophoenix madagascariensis Coccothrinax argentata Coccothrinax miraguama Cocos nucifera album chinensis Phoenix dactylifera Pritchardia pacifica Pritchardia Pritchardia vuylstekeana Pritchardia elegans Ptychosperma Ptychosperma

PLANT

HOST

EPORTED 8. R Most host plants are reported with no information about which RPM stage was found. The establishment of a multigenerational col found. RPM stage was Most host plants are reported with no information about which by Pellegrano (2006) as Welbourn Host plants with * are cited by a b amily Plant species Reference ABLE Arecaceae Arecaceae Aceracee Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae F Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae T 288 Florida Entomologist 92(2) June 2009 b ony has not always been documented. ony has not always K. Griffiths, personal communication Griffiths, K. Etienne & Fletchmann (2006) Kane & Ochoa (2006) Kane & Ochoa (2006) Gupta (1984) . L.) (2005) Kane et al. a INDICA

. in press Sonn. (2006) Welbourn AOIELLA Cook. (2006)* Welbourn (Cham.) Glassman (2005) Kane et al. R Musa sapientum

.) K. Schum.) K. Etienne & Fletchmann (2006) F. Burtt-Davy Kane & Ochoa (2006) L.F. Welbourn (2006) Welbourn L.F. O. OF H. Wendl. H. Etienne & Fletchmann (2006)

(Mart) Glassman (2006)* Welbourn ieill (L. Lind.) H. Wendl. Lind.) H. (L. (2006) Welbourn L. (= L. V Lam. (2006)* Welbourn Lour. (2005) Kane et al. ( L. (1974) Chaudri et al. Irvine (2006) Welbourn Ruiz & Pavon Ruiz & Pavon Etienne & Fletchmann (2006) Burret personal communication Griffiths, K. Rumph. (2006) Welbourn, Banks ex Dryard Etienne & Fletchmann (2006) Colla (2005) Kane et al. Colla (2005) Kane et al. Lodd. ex J. A. & J. H. Schult. H. & J. A. ex J. Lodd. personal communication Griffiths, K. Becc. personal observation Cocco, A. Bory (2006) Welbourn (L.) L. (2006)* Welbourn (Thunb.) A. Henry ex RehderA. (Thunb.) (2006)* Welbourn SPECIES sp. personal communication Griffiths, K.

. spp. Kane & Ochoa (2006) sp sp. Kane & Ochoa (2006) basilicum

sp. sp. PLANT

spp. sp. odyetia bifurcata ashingtonia filifera ashingtonia robusta ashingtonia HOST hrinax radiata eitchia arecina eitchia eitchia andanus utilis andanus

W Cassine transvaalensis concolor Schippia Syagrus romanzoffianum Syagrus schizophylla W W W Eucalyptus Eugenia Olea P P madagascariensis Musa corniculata Musa Phaseolus bihai Heliconia caribaea Ocimum T V V Musa uranoscopus Musa x paradisiaca EPORTED ) R ONTINUED 8. (C Most host plants are reported with no information about which RPM stage was found. The establishment of a multigenerational col found. RPM stage was Most host plants are reported with no information about which by Pellegrano (2006) as Welbourn Host plants with * are cited by a b andanaceae andanaceae abaceae amily Plant species Reference ABLE Arecaceae Celastraceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Arecaceae Myrtaceae Myrtaceae Oleaceae P P Strelitziaceae Strelitziaceae Zingiberaceae Musaceae Musaceae F HeliconiaceaeHeliconiaceae Heliconiaceae Heliconiaceae Heliconiaceae Lamiaceae Heliconia sp. (2006) et al. Peña Arecaceae Arecaceae Arecaceae Musaceae Arecaceae Arecaceae Musaceae Musaceae Musaceae F T Cocco & Hoy: Laboratory Rearing of the Red Palm Mite 289

Cavendish, Robusta, and Williams) and plantain (Apem, Cents Livre, Ordinary, Dwarf French, and Horn) varieties (N. Commodore, personal commu- nication). The banana and plantain varieties we tested in our leaf disc and potted tree bioassays were different from those reported from the East- ern Caribbean, except for the Dwarf variety. Despite these reports, RPM fe- males did not establish and were often observed b not feeding on the banana and plantain varieties tested in our leaf disc and whole potted tree quar- antine bioassays. However, in the same experi- ments, RPM females established and fed continu- ously on coconut leaf discs. Among the banana and plantain varieties tested, RPM females sur- vived longer and were observed feeding more of- ten on Glui Kai discs than on other varieties, sug-

ony has not always been documented. ony has not always gesting that Glui Kai is the most palatable ba- nana variety tested.

Etienne & Fletchmann (2006) The behavior of RPM females may be a better index of host suitability than the oviposition rate because frequent observations of females not feeding, drowned or dead suggest that females are searching for a suitable host on which to es-

tablish and feed. The RPM progeny (F1 females) reared on banana discs that reached adulthood did not deposit eggs and no established colony of the RPM was obtained on banana leaf discs or potted banana trees. The reason(s) for the failure to establish RPM females and immatures on banana trees and leaf discs in quarantine are unclear. In our quaran- tine bioassays, the establishment of RPM fe- . ) a males collected from coconut or banana trees was evaluated on newly prepared and 3-d-old ba- nana leaf discs, but neither the original host of INDICA

. Nicolaia the RPM (coconut or banana) nor the age of the leaf discs appear to promote the establishment of RPM colonies on banana leaf discs. Physical and/ in press AOIELLA or chemical modifications of banana and plan- R tain leaf discs could have repelled RPM females, OF but the experiment with potted banana trees did not result in the establishment of a stable colony (Pers.) B. L. Burtt & R. M.Sm. Burtt & R. L. B. (Pers.) personal communication Griffiths, K. (Jack.) M. Sm. (= Sm. M. (Jack.) of the RPM. Characteristics of the cuticle or SPECIES quantity of wax on the abaxial surface might make some banana or plantain varieties more sp. (2006) et al. Peña PLANT

suitable for the RPM than others. Consistent with this hypothesis, while sampling the RPM

HOST from 2 heavily infested banana trees of unknown

Alpinia zerumbet Zingiber variety(ies) in Lake Worth (Jun 2008), an unin- fested banana tree of unknown variety was ob- served less than 1 m away. A sprout from the EPORTED base of the infested tree was collected, potted, ) R and a new banana/plantain tree was grown in the quarantine laboratory in Gainesville. RPM females were released on leaf discs and on young leaves of the growing shoot under quarantine ONTINUED conditions, but RPM did not establish, perhaps because the shoot contained only young leaves 8. (C while the “mother” tree had RPM on mature Most host plants are reported with no information about which RPM stage was found. The establishment of a multigenerational col found. RPM stage was Most host plants are reported with no information about which by Pellegrano (2006) as Welbourn Host plants with * are cited by a b amily Plant species Reference ABLE leaves. Zingiberaceae Zingiberaceae Zingiberaceae F T 290 Florida Entomologist 92(2) June 2009

Field observations on both coconut and banana species (A. Cocco, personal observation), yet needle trees revealed that mature leaves were more of- palm might be a host based on our laboratory ob- ten infested by the RPM than young leaves (A. servations. At the same site, the cabbage palm and Cocco and M. A. Hoy, personal observations). the scrub palmetto Sabal etonia Swingle ex Nash Young leaves might be unsuitable for the RPM be- (closely related to the dwarf palmetto) were in- cause of higher concentration of secondary plant spected, but no RPM was found, possibly confirm- compounds than old leaves. For some trees, young ing our finding that they are not hosts. Observa- leaves are reported to have higher levels of sec- tions conducted in 13 counties in Florida until Aug ondary metabolites such as alkaloids, phenols, 2008 report only the Florida thatch palm and the flavonoids, and terpenoids than older leaves (Ber- Florida silver palm Coccothrinax argentata (Jacq.) nays & Chapman 1994). The desert clicker Lig- L. H. Bailey among native palms are a host of the urotettix coquilletti McNeill (Orthoptera: Acrid- RPM; both palms are included on the Florida en- idae) habitually feeds on older leaves of Larrea dangered and threatened plant list (Coile & Gar- tridentata because they contain a lower concen- land 2003) (A. Cocco, personal observation; K. M. tration of the deterrent nordihydroguaiaretic acid Griffiths, personal communication). The ability of than young leaves (Chapman et al. 1988). Wood- R. indica to establish and spread on native and or- head (1983) observed that young leaves of some namental palms raises important questions about varieties of Sorghum sp. are unsuitable for the the potential impact of the RPM on natural land- migratory locust Locusta migratoria L. (Ortho- scapes. Our quarantine experiments and field ob- ptera: Acrididae) because they contain a specific servations suggest that RPM adults can deposit wax compound, while older leaves are accepted. eggs and survive some days on unsuitable hosts, so To clarify whether the leaf age affects the estab- host range studies should report plants as suitable lishment of the RPM on banana or plantain trees, hosts only when all stages of RPM are observed, in- young and old leaves of the same tree could be in- dicating that multigenerational colonies were es- fested under field conditions with known num- tablished. bers of RPM females. In our experiments, because A multigenerational RPM colony has estab- RPM females established on coconut leaf discs lished on coconut potted trees and stable colonies and trees under the same climatic conditions as can be maintained on coconut leaf discs by cutting these of the banana discs and potted trees, we be- the discs into pieces every 3 weeks and placing lieve that abiotic factors such as temperature, small portions of the infested old disc on new RH, and photoperiod did not affect the establish- discs, allowing the RPM to move from the old to ment of the RPM. the new discs. Our results suggest that coconut Native and ornamental palms such as saw pal- leaf discs and trees are the most suitable hosts for metto, cabbage palm, needle palm, dwarf pal- RPM females and a better host on which to rear metto, European and Chinese fan palms are com- the RPM in quarantine than the other hosts mon woody plants on the natural landscape of tested. Florida and are used for landscaping homes, parks, and streets (Black 2003a, 2003b). In addi- ACKNOWLEDGMENTS tion, saw palmetto and needle palm are economi- cally important palms (Tanner et al. 2002; Coile & The authors thank Hector Perez of the University of Garland 2003). Extracts of saw palmetto fruits Florida, Department of Environmental Horticulture, are used to treat symptoms of benign prostatic hy- for palm identifications and James Colee of the Univer- perplasia (Gordon & Shaughnessy 2002). Our re- sity of Florida, Department of Statistics, for statistical sults indicate that saw palmetto, dwarf palmetto, consultation. Don Goodman of the Kanapaha Botanical Gardens, Gainesville, FL, and Jerry Behan of the Deer- and cabbage palm leaf discs are not suitable hosts field Beach Arboretum, Deerfield Beach, FL, kindly al- for the RPM in quarantine. Preliminary labora- lowed sampling of palms, Karolynne Griffiths of the tory tests indicated that the Chinese fan palm United States Department of Agriculture—APHIS— Livistona chinensis (Jacq.) R. Br. and the Euro- PPQ suggested sites for sampling the RPM from coco- pean fan palm Chamaerops humilis L. also failed nuts and bananas and provided information of hosts to support establishment of RPM colonies (H. from which RPM were collected. This research was sup- Bowman & M. A. Hoy, unpublished). ported in part by the Davies, Fischer and Eckes Endow- Although the RPM completed a generation on ment in Biological Control to M.A. Hoy and a contract needle palm discs, it exhibited a doubled develop- (07-8312-0541-CA) from USDA—APHIS—PPQ. ment time and higher mortality of eggs and imma- tures, and it is unclear if a multigenerational col- REFERENCES CITED ony on needle palm leaf discs can be established. BERNAYS, A., AND CHAPMAN, R. F. 1994. 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